Kenworth Truck Company is an American truck manufacturer. Founded in 1923 as the successor to Gersix Motor Company, Kenworth specializes in production of heavy-duty (Class 8) and medium-duty (Class 5–7) commercial vehicles. Headquartered in the Seattle suburb of Kirkland, Washington, Kenworth has been a wholly owned subsidiary of PACCAR since 1945, operating alongside sister company (and marketplace rival) Peterbilt Motors.
Kenworth marked several firsts in truck production; the company introduced a raised-roof sleeper cab, and the first heavy-duty truck with an aerodynamically optimized body design. The Kenworth W900 has been produced continuously since 1961, serving as one of the longest production runs of any truck in automotive history. The K100 was also released in 1961.
